Nobody is understanding this to mean, "Oh, yeah, the Japs have a bit of trouble with their Ls, they probably do say Are-Oh-Are when they're amused". Everybody apart from you is understanding this to mean, "Oh, yeah, the well-known cliché about Japanese people is that they say 'r' instead of 'l' sometimes, so substituting 'r' for 'l' in LOL gives you ROR. How funny. Isn't it a bloody good job they attacked Pearl Harbour when the aircraft carriers were out?"
Incidentally, I recommend applying the same logic to my first post.

we don't pronounce LOL "ellohell", we pronounce it "lol"
so a theoretical native Japanese speaker wouldn't pronounce it "eruoeru", but might pronounce it "ror", with "r" being the soft japanese r/l sound.
I dunno, if we're pulling rank appeals to authority, I lived in Japan for two years and got my sankyu JLPT, and I got it right away - maybe you're just a bit funny in the head?